Skid and pallet handling lift truck



April 9, 1957 D. HARPER E1- AL 2,788,147

SKID AND PALLET HANDLING LIFT TRUCK 5 Sheets-Sheet 1 Filed Jan. 3, 1955 fizyrz zorts: par/2d Jar v67 110 a Smart/I Zea er Pen-ables new April 9, 1957 D. HARPERET AL sxm AND PALLET HANDLING LIFT TRUCK 5 Sheets-She Filed Jan. 5, 1955 w 2% a Wm 4W 4 6 m 2m JW M April 9, 1957 D. HARPER EIAL sxm AND PALLET HANDLING LIFT mucx 5 Shee ts-Sheet 3 Filed Jan. 3. 1955 We)" 54/2272 e6 Z es or "/zeys .lll-r l April 1957 D. HARPER ETAL 2,788,147

SKID AND PALLET HANDLING LIFT TRUCK i Filed Jan. 3, 1955 5 Sheets-Sheet 4 FIE-5.4

April 9, 1957 D. HARPER ETAL sxm AND PALLET HANDLING LIFT TRUCK 5 Sheets -Sheet 5 Filed Jan. 3, 1955 S AND PALLET HANDLING LIFT TRUCK David Harper, Crawfordsville, Lester R. Peebles, Darlington, and Lloyd R. Swank, Crawfordsville, Ind., assignors to R. R. Donnelley & Sons Company, a corporation of Delaware Application January 3, 1955, Serial No. 479,276

8 Claims. (Cl. 214-621) This invention relates to an improved lift truck construction by means of which the truck may lift a platform supporting a load, and may also lift the separate unattached skids upon which the platform is supported.

In the handling of materials on a load support which includes a platform it is necessary that the platform be supported far enough off the floor that a lift truck fork or table may be inserted under the platform to pick it up. This is normally accomplished by placing the platform on top of a pair of parallel skids. In order to economize on storage space insofar as the platforms and skids are concerned, the platforms are commonly separate from the skids so that they may be piled one on top of another in a small space, and the separate skids may he stood on end in a corner, or otherwise stored in a small area also.

This has meant that when a lift truck operator lifts a platform off the skids on which it has been standing he must then get olf the truck, pick up the skids and put them on top of the load or across the lift truck body, and when he reaches the point at which the load is to be put down he must again get off the truck, place the skids where he wants them, and then set the platform down upon the skids. Obviously this procedure is very wasteful of time and energy.

In accordance with the present invention each side of a lift truck table is provided with a pair of auxiliary arms which may be extended laterally into the spaces between the legs on the skids, so that when the truck lift member is elevated to lift the platform and its load the arms beneath the skids lift the skids along with the load. Movement of the lateral extension arms is controlled by means of a hydraulic valve lever which may be operated by the lift truck operator from the driving station, or operators station of the lift truck.

The invention is illustrated in the preferred embodiment in the accompanying drawings in which:

Fig. 1 is a fragmentary side elevational view of a lift truck which has been provided with the auxiliary lifting arms of the present invention;

Fig. 2 is a section taken as indicated along the line 2-2 of Fig. 1;

Fig. 3 is a section taken as indicated along the line 3-3 of Fig. 1;

Fig. 4 is a section taken as indicated along the line 4-4 of Fig. l; t

Fig. 5 is an enlarged fragmentary section taken as indicated along the line 5-5 of Fig. 4;

Fig. 6 is a section taken as indicated along the line 6-6 of Fig. 5 with the auxiliary lift arm shown in solid lines in its retracted position and in broken lines in its extended position;

Fig. 7 is a fragmentary view similar to Fig. 5 showing the position of the mechanism with the arm in extended position;

Fig. 8 is an enlarged fragmentary sectional view illustrating the safety break-away latch to prevent overloading States Patent ice of the lift arm, the outer portion of the arm being shown in solid lines in its normal position and in broken lines in its unlatched, break-away position; and

Fig. 9 is an enlarged fragmentary sectional View showing the attachment of an auxiliary lift arm to its operating pinion.

Referring to the drawings in greater detail, and referring first to Figs. 1-4, a lift truck, indicated generally at 10, has a wheeled frame 11 at one end of which is an operators station 12 from which the operation of the lift truck is controlled, and forward of the operators station is a housing 13 containing batteries and an electric motor for driving the truck. A vertically extending lift trackway 14 accommodates lift means, indicated generally at 15.

As best seen in Fig. 2 the lift means 15 includes a pair of upright supporting members 16 which embrace the trackway 14 and are provided with guide wheels 17 riding within the trackway, lift sprockets 18 to accommodate continuous lifting chains 19 for mechanically raising and lowering the lift means, and a forwardly extending lift table 20 which, as best seen in Fig. 3, has a heavy upright skirt 21. The front of the chassis is quite narrow so that the lift table 20 may be lowered until the skirt 21 surrounds the front of the chassis and the sides of said skirt flank the front wheels of the truck. Suitable controls are provided so that both the travel of the lift truck and the raising and lowering of the lift means is controlled by an operator standing at the operators station at the rear of the truck. The mechanism just described is that of a standard platform type lift truck and it is not believed that any further detail is necessary. The present invention consists of the auxiliary lifting mechanism which is about to be described.

Referring now particularly to Figs. 4-9, the auxiliary skid lift mechanism of the present invention includes a pair of rear auxiliary lift arms 22 and a pair of front auxiliary lift arms 23 which are mounted on pivots 24 and 25, respectively, in the skirt 21 of the lift table 20. The pivots 24 and 25 are adapted to be rotated so as to move the auxiliary lift arms 22 and 23, respectively, between retracted positions in which they lie in recesses 21a cut in the skirt 21 as seen in solid lines in Fig. 6, and extended, or lifting positions as seen in the broken lines of Fig. 6. As best seen in Fig. 4 the front auxiliary lift arms 23 have their outer, or lifting portions 23a disposed at an angle so that they may lie flush with the tapering forward margins 21a of the skirt 21.

The operating mechanism for the rear auxiliary arms 22 and the front auxiliary arms 23 is identical, so only the mechanism for one of the front arms will be described in detail with reference to Figs. 5-9. Mounted on the inside face of the skirt 21 is a hydraulic cylinder 26 which is provided with a fluid line 27 by means of which it is connected to a distributor head 28, seen in Figs. 2 and 3. The rear hydraulic cylinders 29 for the rear lift arms 22 are connected by conduits 30 with the distributor 28, and the distributor 28 is connected in turn by means of a main fluid line 31 with a master cylinder 32 which is controlled from the operators station 12 by means of a control handle 33 (see Fig. 1).

Referring again to Figs. 5-9, the piston rod 26a of the hydraulic cylinder 26 is provided at its outer end with a coliar 34 which serves as a stop for a coil compression spring 35 mounted in a spring carrier 36 on the skirt 21. A set screw 37 is provided to adjust the tension on the spring 35. An operating lever 38 which is mounted on a pivot 39 is pivotally connected at 40 to the piston rod 26a and at 41 to a rack 42 which is slidably mounted in a rack bracket 43 adjacent the pivot 25 for the auxiliary lift arm 23. The rack 42 engages a pinion 44 which is i 3 mounted at the inner end of the lift arm 23 surrounding the pivot 25, so that movement of the rack 42 effects rotation of the pinion 44 and thus may swing the auxiliary lift arm 23 between its retracted position and its extended position. An auxiliary coil tension spring 45- is secured to a spring pin 46 on the lever 38 and to a stud 47 on the skirt 21.

As best seen in Fig. 8 the outer end 23a of the lift arm is pivotally mounted on a pin 23b so that it may swing downwardly with respect to the inner portion of the arm 23, and a spring pressed latch plunger 23s on the outer arm portion 23a engages in a recess 23d of the inner arm portion. This construction provides a safety breakaway so that if the auxiliary lift arms 22 and 23 engage the skids S before the table 20 is in lifting position beneath the platform P the latches 230 may be disengaged from the recesses 23d and permit the outer ends 23a of the auxiliary lift arms to swing down, preventing damage to the arms or the operating mechanism. As seen in Fig. 3, the rear lift arms are also constructed with breakaway outer portions 22a which are mounted on pivots 22b and provided with latch members 220.

. The operation of the device is believed to be clear from the foregoing description. With the lift table 20 in its lowered position the operator maneuvers the lift truck 10 to position the platform beneath a platform P and between the skids S upon which the platform is supported. The lift table is raised into contact with the platform P, and the operator then moves the control lever 33 to swing the outer portions of the auxiliary lift arms 22 and 23 into engagement with the skids S. Upon further elevation of the lift table 20 both the platform and the skids will be lifted together, and may be moved as a unit to a storage position where the platform and skids are lowered to a desired location, the arms 22 and 23 are retracted, and the lift table 20 disengaged from the load.

The foregoing detailed description is given for clearness of understanding only and no unnecessary limitations are to be understood therefrom, as some modifications will be obvious to those skilled in the art.

We claim:

1. In a lift truck having an operators station and movable lift means which is adapted to be positioned between a pair of skids having longitudinally extending openings and which is controlled from the operators station to lift a platform off said skids: extension means mounted on opposite sides of said lift means for lateral movement outwardly from the lift means, said extension means including a plurality of arms which are spaced longitudinally on the two sides of the lift means and adapted to enter the openings of the skids; actuating means for selectively moving said extension means laterally to position said arms in the openings in the skids so that said skids may be supported on the arms of the extension means and lifted thereby as the lift means lifts the platform, or for retracting said extension means; and control means for said actuating means which is operable from the operators station, whereby the lift truck may lift and move said skids with said platform.

2. In a lift truck having an operators station and movable lift means which is adapted to be positioned between a pair of skids having longitudinally extending openings and which is controlled from the operators station to lift a platform off said skids: selectively, laterally, movable extension means mounted on opposite sides of said lift means; a master fluid cylinder on the lift means; a plurality of separate fluid cylinders communicating with said master cylinder; means linking said separate fluid cylinders to said extension means for selectively moving said extension means laterally into the openings in the skids so that said skids may be supported on the extension means and lifted thereby as the lift means lifts the platform, or for retracting said extension means; and control means for said actuating means which is operable from the operators station, whereby the lift truck may lift and move said skids with said platform.

3. In a lift truck having an operators station and movablc lift means which is adapted to be positioned between a pair of skids having longitudinally extending openings and which is controlled from the operators station to lift. a platform off said skids: selectively laterally movable extension means mounted on opposite sides of said lift means; vertically pivotable lifting elements at the outer extremities of said extension means; snap latch means for retaining said lifting elements n0rmally in a substantially horizontal plane; actuating means for selectively moving said extension means laterally into the openings in the skids or retracting said extension means; and control means for said actuating means which is operable from the operators station, whereby the lift truck may lift and move said skids with said platform.

4. The device of claim 1 in which the extension means comprises a pair of arms mounted on each side of the lift means for pivotal movement in a horizontal plane.

5. The device of claim 1 in which the extension means retracts into recesses in the lift means.

6. In a lift truck having an operators station and movable lift means which is adapted to be positioned between a pair of skids having longitudinally extending openings and which is controlled from the operators station to lift a platform off said skids: a pair of arms pivotally mounted on opposite sides of the lift means for horizontal swinging movement between a retracted position and a laterally extending position projecting into the openings in the skids; actuating means for swinging said arms between said positions, said actuating means including a master fluid cylinder which communicates with a separate fluid cylinder for each arm; and control means for said actuating means which is operable from the operators station, whereby the lift truck may lift and move said skids with said platform.

7. The device of claim 6 in which the arms are mounted on upright pinions, and the separate fluid cylinders are connected to racks engaged with said pinions to rotate the pinions.

8. The device of claim 6 in which the arms retract into recesses in the lift means.

References Cited in the file of this patent UNITED STATES PATENTS 1,311,165 Hennessy July 29, 1919 1,316,239 Hogander Sept. 16, 1919 2,509,023 Vogel et. a1. May 23, 1950 2,543,254 Osborn Feb. 27, 1951 2,624,470 Geist Jan. 6, 1953 2,656,062 Thomas Oct. 20, 1953 

